186 Partial loss of AKAP1 promotes cardiac dysfunction, gut barrier abnormalities, and alteration of gut microbiota composition during ageing

Aims Mitochondrial A-kinase anchoring proteins (mitoAKAP) encoded by the Akap1 gene promote Protein Kinase A mitochondrial targeting, regulating mitochondrial structure and function, reactive oxygen species production, and cardiomyocyte survival. Whether mitoAKAP levels play a role in cardiac ageing, gut barrier integrity and gut microbiota composition is currently unknown. The aim of this study was to highlight the complex interplay between cardiac dysfunction, gut barrier integrity, gut microbiota composition and ageing in young (6-month-old, 6 m) and old (24-month-old, 24 m) wild type (wt) and Akap1 heterozygous mice (Akap1+/−). Methods and results Cardiac function was noninvasively analysed by echocardiography in 6 m and 24 m wt and Akap1+/− mice. Gut microbial DNA was extracted and gut microbiota composition was analysed by Illumina Mi-Seq analysis. Bioinformatics analysis was carried out to identify major intestinal populations. Alpha diversity within each sample was determined, and then analysed according to genotype and age; then, inter-sample diversity was determined. For each dataset, we used UniFrac to calculate the differences between microbial communities based on phylogenetic distance between taxa sets in a phylogenetic tree. Bioinformatics analyses were performed using the analysis of similarities (ANOSIM). To evaluate the role of mitoAKAPs in intestinal permeability, we analysed intestinal junction proteins expression levels in colon samples of all groups. Variance analysis was performed to determine significance among the groups. Partial loss of Akap1 accelerated the progression of cardiac dysfunction in 24 m mice, as demonstrated by a significantly lower % fractional shortening (%FS) compared to 24 m wt mice (%FS, wt 6 m: 60 ± 3; Akap1−/+ 6 m: 58 ± 5; wt 24 m: 49 ± 6*; Akap1−/+ 24 m: 39 ± 12*§; *P Conclusions Partial Akap1 deletion plays an important role in the progression towards HF and modulates colon permeability and gut microbiota composition during ageing. This work highlights the complex interplay between gut microbiota and development of cardiac dysfunction, and characterization of these processes might lead to the development of new diagnostic and therapeutic approaches for cardiac dysfunction.